Oliver Pybus

Professor Oliver Pybus

Research Fellow

Organisation

University of Oxford

Research summary

Viruses evolve incredibly quickly - the genetic change that accumulates over a few months in some virus populations is equivalent to hundreds of thousands of years of animal evolution. Through their high rates of evolution, viruses quickly accumulate genetic changes that make them resistant to new drugs or enable them to ‘escape’ from our immune defences. A second consequence of this is that the genetic code of viruses accumulate differences as they pass from person to person, which means that we can reconstruct where and when a virus has spread by analysing the pattern of genetic differences among infections. Some of my time is spent developing new statistical methods and computer programs that can perform the complex calculations required to analyse genome sequences. By combining virus genomes sampled throughout the world over several decades I can reconstruct the epidemic history of a virus, which helps to predict its future spread. This year I used this technique to understand the evolution and origin of the new H1N1 'swine influenza'. Within a couple of weeks of the new virus being discovered, I was able to show that the epidemic originated in pigs and had already been present (but undetected) in humans for several months. I am also interested in how viruses evolve over the duration of a single infection. For example, I study how HIV/AIDS and the hepatitis C virus use evolution to evade our immune responses and therefore sustain damaging persistent infections that last many years.